Frequencies for first 10,000 rows of rollover variable in person dataset :

   Rollover |
       Type |      Freq.     Percent        Cum.
------------+-----------------------------------
         -1 |         25        0.25        0.25
          0 |      6,765       67.65       67.90
          1 |      2,041       20.41       88.31
          2 |        254        2.54       90.85
          9 |         45        0.45       91.30
          . |        870        8.70      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 18 Apr 2016